Surface patterning is crucial for the progress of key enabling technologies (KETs) such as advanced manufacturing, microelectronics, nano/biotechnology and photonics. The current paradigm in surface patterning is optical projection lithography (OPL), a paradigm designed for high-resolution. However, emerging green technologies like micropatterned photovoltaics (PV) require high quality patterning at scale/throughput that is hardly attainable by OPL economically and sustainably. Importantly, half-pitch resolutions on the tens of μm-scale are totally acceptable for such applications, which does not justify the use of high-end OPL. In these cases, OPL is unsuited, because it relies on disposable masks with extremely high embodied energy. While the key asset of OPL is the mask, it is the component that currently makes it low-throughput and energy/material inefficient. Extensive efforts have been directed to develop maskless strategies, but most fall short when it comes to throughput and design flexibility. REMAP envisions a radically new and green surface patterning technique based on the spontaneous formation of reusable magnetic masks. Such masks are possible using fully adjustable and reversible interactions of "magnetorheological electrolytes" (MRE) on a substrate and microstructured magnetic fields generated by a permanent array of electromagnets below the substrate. By selectively activating each micro-electromagnet, it is possible to modulate the intensity and shape of the magnetic field (hence the mask) over space and time. This way, REMAP enables high-throughput area-selective additive and subtractive patterning on a surface at room temperature and pressure. Furthermore, the newly devised MREs and the tuneable magnetic array developed within REMAP will pave the way to a plethora of future applications from lab-on-a-chip biomedicine, NMR analysis and smart fluids for robotic space exploration.